The use of field emission cathodes in the design of x-ray tubes requires the placement of a cathode assembly with a small distance from the anode, complicating the output of radiation. Most acute this problem occurs when generating a relatively soft spectrum with wavelengths of 1-10 nm: in this case, the accelerating voltage does not exceed several kilovolts, and the inter-electrode distance composes several hundred micrometers. In this work, we experimentally demonstrated the applicability of beryllium-based submicron films as “shot-through” anodes for generating the Be K line ( = 11.4 nm) and the associated bremsstrahlung spectrum. In particular, the characteristic radiation of a tube with a field emission blade cathode and a Be film anode was recorded within the scheme of a grazing incidence grating spectrometer. The characteristics of beryllium films necessary for the development of X-ray tubes of this type with a higher output power are determined.

We demonstrate the possibility of manufacturing Be-based ultrathin films with high transmission at wavelengths of 11.4 and 13.5 nm. For free-standing films of Be and Be-based multilayer structures (Si/Be, ZrSi2/Be, Be/BexNy, Zr/Be, Ru/Be, Mo/Be), we determine the thresholds of the absorbed power at which over a short period (tens of minutes) of vacuum annealing, initially sagging free-standing films became visibly stretched over the hole. Of the film structures tested here, the Be/BexNy structure (with beryllium nitride interlayers) showed the highest threshold for the absorbed power (1 W/cm2). However, due to the low strength of this structure, ZrSi2/Be, Mo/Be, and Be films seem to be more promising for the manufacture of a full-size pellicle. Long-term vacuum annealing of Mo/Be and Be ultrathin films showed that they could withstand 24 hours of vacuum heating at an absorbed power density of 0.2 W/cm2 (film temperature ~250°C) without noticeable changes in EUV transmission or sagging of films. With comparable transmission (~83% at 13.5 nm and ~88% at 11.4 nm), a multilayer Mo/Be structure with a thickness of 30 nm appears to be preferable, as it shows less brittleness than a monolayer Be film with a thickness of 50 nm.